Background: Enterotoxigenic Escherichia coli (ETEC) is the main cause of fatal diarrhea in
piglets during the first week of life and over the time of weaning. Pathogenesis of ETEC-causing diarrhea
involves intestinal colonization mediated by fimbriae. Although, both IgY and egg yolk phosvitin
(PV) possess antimicrobial activity, their combined activity has not been explored. A combination of
IgY specific for ETEC and metal-chelating PV may show synergistic effect in reducing the growth of
ETEC by inhibiting bacterial proliferation and stipulating protection against ETEC infection.
Objective: The goal of this study was to determine the effects of anti-ETEC IgY and PV on in vitro
growth inhibition of ETEC strains possessing K88 and K99 fimbriae prevalent in the porcine population.
Methods: Anti-K88 and -K99 IgY antibodies were obtained from egg yolks of 23-week-old Single-
Comb White Leghorn hens immunized with K88 and K99 fimbriae of ETEC, respectively, with high
titres sustained over 6 to 8 weeks of the immunization period. Specific IgY, PV, and PV-hydrolysate
from alcalase-hydrolysis under high hydrostatic pressure (PVH-Alc-HHP) alone or in combination,
were used to treat ETEC K88 and K99 cultures at optimal concentrations of 100 μg/mL, 1 mg/mL, and
1 mg/mL, respectively, for 24 h.
Results: PVH-Alc-HHP demonstrated the highest degree of hydrolysis, 38.9%. Combined use of IgY
and PVH-Alc-HHP showed the highest bactericidal effect resulting in ETEC K88 and K99 growth inhibition
of 2.8 and 2.67 log CFU/mL, respectively.
Conclusion: Combined IgY-PVH effectively control ETEC, therefore holds a great potential for microbial
control in veterinary pharmaceutical industry.